We propose to develop a small animal model of a prevalent human cancer that we believe will be suitable for the study of the complex interrelationship between tumor progression and the immune response. For these initial studies our work will focus on ovarian adenocarcinoma because of its medical significance, the availability of appropriate specimens, and the anatomically confined nature of the disease. The development of this model depends upon three elements: 1) our ability to separate human malignant ovarian ascites into highly enriched populations of tumor cells, lymphocytes, and monocytes by counterflow centrifugal elutriation (CCE); 2) Our experience with the establishment of human lymphoid xenografts in severe combined immunodeficient (SCID) mice; and 3) The published work of other laboratories indicating that human ovarian neoplastic xenografts can be established in conventional nu/nu mice. Ovarian ascites cells are available in large number as a byproduct of therapeutic paracentesis. We are able to process up to 2xl0-10 cells in a single elutriation run, providing ample numbers of viable tumor cells, even when they comprise a relatively small proportion of the ascites or are admixed with infiltrates of low overall viability. Because this tumor is primarily confined to the peritoneum, it is particularly well suited for xenografting studies; both human tumors and human lymphocyte/monocyte populations can be established within the peritoneal cavities of SCID mice. The scope of the present proposal is to: 1) Optimize the establishment of purified human tumor cells in SCID mice; 2) Assess the effect of co-inoculation of tumor plus tumor infiltrating lymphocytes, monocytes and peripheral blood mononuclear cells; and 3) Provide a preliminary characterization of in vitro correlates of tumor specific immunity as measured using tumor infiltrating lymphocytes and monocytes. In doing so we hope to provide a system that will allow us to test hypotheses concerning potential mechanisms by which tumor evades immune eradication, particularly at the level of effector cell generation. Although the present proposal focuses on ovarian cancer, we believe that this methodology will be applicable to other neoplasms as well. The ability to isolate tumor infiltrating inflammatory cells in high number and purity makes this system particularly well suited to future studies of tumor specific immunity.